The technique of bonding electronic parts together by the use of a solder is known. For example, the use of the technique of mixing a filler with a solder or the technique of forming an alloy having martensitic transformation properties under or around a solder is proposed regarding bonding electronic parts together by the use of a solder in order to, for example, relax stress in a bonding portion or suppress the appearance of a crack.
Japanese Laid-open Patent Publication No. 09-295184
Japanese Laid-open Patent Publication No. 2001-24021
With an electronic device including a group of electronic parts bonded together by the use of a solder or an electronic apparatus (electronic equipment) including the electronic device, crystal grains in a solder contained in a bonding portion may coarsen due to heat generated in temperature rise and fall processes which accompany the operation. If the crystal grains in the solder contained in the bonding portion coarsen, a crack tends to propagate. This may lead to deterioration in the reliability.